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[SOLVED] What it the Output Template for mobility, un

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rmanalo

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Hello everyone,

I'm trying to extract the sub-threshold slope, m, by plotting it in HSPICE from the equation Id=SµnVt^2((Vgs-Vth)/mVt) from this m=(vgs-vth)/Vt*ln(Id/SµnVt^2). This is true provided that Vds>4Vt. Now from HSPICE documentation there are parameters called "Output Templates" for example LV9(M1) is the Vth of M1 and so on but I can't seem to find the output template for electron mobility. Is anyone familiar with this? attached is a sample of my netlist code.

sampe document.JPGsubthreshold slope m netlist.JPG

Also, if anyone has a better suggestion for extracting the typical value for m, your input is highly appreciated.

Best Regards,
rmanalo
 

I don't think HSPICE has an Output Template for the electron mobility µn - at least I've never seen such. You probably have to calculate it yourself - as HSPICE is doing it.
 
erikl said:
I don't think HSPICE has an Output Template for the electron mobility µn - at least I've never seen such. You probably have to calculate it yourself - as HSPICE is doing it.
Click to expand...

Thank you for replying erikl. I was wondering what your thoughts are on calculating the subthreshold slope factor, m, instead since that's real goal I'm after. (Or should I even need to calculate it in the first place? - and say "simulation result is #% lower or higher than the calculated/expected value") I'm doing hand calculations on subthreshold design, should I use the typical value stated in books (1.2-1.5)?
 

The MOSFET models state the low field electron (or hole) mobility parameter as U0.

Here are two process dedicated values for the subthreshold slope factor, here called substrate factor n :
View attachment Substrate-factor.pdf
View attachment Binkley__substrate-factor.pdf

I don't think it's worth to find better values, but if you really want to extract these values yourself, you could do this by simulation with the right models, or by measuring MOSFETs, extracting this parameter value from the slope of its Ids vs. Vgs characteristics.
 
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